#include "string.h"
#include <iostream>



int main()
{
  
  String s1("hello"); 
  String s2("world");
    
  String s3(s2);
  String s4;
  std::cout << s3 << std::endl;
  
  s3 = s1;
  std::cout << s3 << std::endl;     
  std::cout << s1 << std::endl;  
  std::cout << s2 << std::endl;      
}